Ultrasound images provide an operator with a wide range of information about a patient. To gain more information, it often is necessary to reproduce the ultrasound imaging environment that existed when an ultrasound image was created. For example, when an operator compares ultrasound images of a patient over time or performs serial studies on a plurality of patients, it is necessary to ensure that patients are imaged in the same way to remove ultrasound imaging system setup variability as a source of discrepancy. Reproduction of an ultrasound imaging environment is made extremely difficult or impossible due to the variations in, for example, the ultrasound system, the transducer, environmental noise, thermal and electrical noise, transducer placement, patient physiological change, operator placement of the transducer on the body, and the amount of acoustic coupling between the transducer and the body.
Another source of difficulty in reproducing an ultrasound imaging environment is due to the large number of operator-controlled parameters that adjust the transmission of the ultrasound beam(s) and the processing, scan conversion, and display of received ultrasound data. Several imaging modes and sub-modes typically are available to an operator. For each of these modes and sub-modes, the operator has a wide range of imaging controls at his or her disposal. These imaging controls include the number of transmit focal beams, the transmit beam focal depths, the transmit power amplitude, the minimum and maximum depth over which the ultrasound image is displayed, the overall receiver gain and localized gain, imaging frequency, spatial filtering, temporal filtering, dynamic range or log compression, postprocessing, Doppler filters, Doppler gate size, the angle of the first and last ultrasound lines, the density of the ultrasound lines, and the size and orientation of the displayed image.
One attempt to reproduce an ultrasound imaging environment is to use pre-stored parameter-setting packages based on an intended clinical application (e.g., obstetrics, peripheral vascular, cardiology). By using the same parameter package, an operator can reduce the variability in ultrasound parameters. The difficulty with this approach is that the operator typically refines the recalled parameters to best visualize the structures of interest on each patient. For example, parameters such as the receiver gain and frequency typically change throughout the course of a clinical ultrasound exam. Thus, even if the operator uses the same parameter package in another imaging session, the imaging environment would not be the same. Accordingly, parameter-setting packages are insufficient for conducting precise, controlled serial studies on a set of patients or for reproducing the imaging parameters that were used to acquire a specific image on a specific patient at some previous point in time.
Another attempt to reproduce an ultrasound imaging environment is to label stored ultrasound images with some of the parameters that were used to create the image. By recalling a stored image, an operator can read the parameters from the stored image and manually adjust the parameters of the imaging system to be identical or similar to those used to acquire the stored image. Several system parameters, however, are difficult or impossible to store in this format. Without storage and retrieval of such parameters, a substantially identical ultrasound imaging environment can not be reproduced.
There is, therefore, a need for an improved ultrasound system and method for facilitating a reproducible ultrasound imaging environment.